﻿using System;
using System.IO;
using System.Reflection;
using System.Security.Cryptography;

namespace RunAsThisUser.ToolSet
{
    public class Tools
    {
        /// <summary>
        /// http://msdn.microsoft.com/en-us/library/system.security.cryptography.rijndaelmanaged.generateiv.aspx
        /// </summary>
        /// <param name="plainText"></param>
        /// <param name="Key"></param>
        /// <param name="IV"></param>
        /// <returns></returns>
        public static byte[] EncryptStringToBytes(string plainText, byte[] Key, byte[] IV)
        {
            // Check arguments. 
            if (plainText == null || plainText.Length <= 0)
                throw new ArgumentNullException("plainText");
            if (Key == null || Key.Length <= 0)
                throw new ArgumentNullException("Key");
            if (IV == null || IV.Length <= 0)
                throw new ArgumentNullException("IV");
            byte[] encrypted;
            // Create an RijndaelManaged object 
            // with the specified key and IV. 
            using (RijndaelManaged rijAlg = new RijndaelManaged())
            {
                rijAlg.Key = Key;
                rijAlg.IV = IV;

                // Create a decrytor to perform the stream transform.
                ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV);

                // Create the streams used for encryption. 
                using (MemoryStream msEncrypt = new MemoryStream())
                {
                    using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                    {
                        using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                        {

                            //Write all data to the stream.
                            swEncrypt.Write(plainText);
                        }
                        encrypted = msEncrypt.ToArray();
                    }
                }
            }


            // Return the encrypted bytes from the memory stream. 
            return encrypted;

        }

        /// <summary>
        /// http://msdn.microsoft.com/en-us/library/system.security.cryptography.rijndaelmanaged.generateiv.aspx
        /// </summary>
        /// <param name="cipherText"></param>
        /// <param name="Key"></param>
        /// <param name="IV"></param>
        /// <returns></returns>
        public static string DecryptStringFromBytes(byte[] cipherText, byte[] Key, byte[] IV)
        {
            // Check arguments. 
            if (cipherText == null || cipherText.Length <= 0)
                throw new ArgumentNullException("cipherText");
            if (Key == null || Key.Length <= 0)
                throw new ArgumentNullException("Key");
            if (IV == null || IV.Length <= 0)
                throw new ArgumentNullException("IV");

            // Declare the string used to hold 
            // the decrypted text. 
            string plaintext = null;

            // Create an RijndaelManaged object 
            // with the specified key and IV. 
            using (RijndaelManaged rijAlg = new RijndaelManaged())
            {
                rijAlg.Key = Key;
                rijAlg.IV = IV;

                // Create a decrytor to perform the stream transform.
                ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);

                // Create the streams used for decryption. 
                using (MemoryStream msDecrypt = new MemoryStream(cipherText))
                {
                    using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                    {
                        using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                        {

                            // Read the decrypted bytes from the decrypting stream 
                            // and place them in a string.
                            plaintext = srDecrypt.ReadToEnd();
                        }
                    }
                }

            }
            return plaintext;
        }

        /// <summary>
        /// http://stackoverflow.com/questions/472906/converting-a-string-to-byte-array
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static byte[] GetBytes(string str)
        {
            byte[] bytes = new byte[str.Length * sizeof(char)];
            System.Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
            return bytes;
        }

        /// <summary>
        /// http://stackoverflow.com/questions/472906/converting-a-string-to-byte-array
        /// </summary>
        /// <param name="bytes"></param>
        /// <returns></returns>
        public static string GetString(byte[] bytes)
        {
            char[] chars = new char[bytes.Length / sizeof(char)];
            System.Buffer.BlockCopy(bytes, 0, chars, 0, bytes.Length);
            return new string(chars);
        }

        public static byte[] IVKey
        {
            get
            {
               return (byte[])Assembly.LoadFrom("DynGen.dll").GetType("DynGen").GetField("ivKey").GetValue(null);
            }
        }

        public static byte[] PrivateKey
        {
            get
            {
               return (byte[])Assembly.LoadFrom("DynGen.dll").GetType("DynGen").GetField("privateKey").GetValue(null);
            }
        }

    }
}
